The present invention relates to bicycle chains and more particularly to a closing link for a bicycle chain that may be used to connect and disconnect adjoining chain links without a tool.
Driving chains for bicycles include chain links pivotably arranged with respect to each other to form a closed loop to transmit the chain driving force. Interior spaces between the chain links receive the teeth of the sprockets or chainrings. To easily remove the chain from bicycle for maintenance, a closing link is provided to disconnect the chain.
DE 44 31 614 A1 discloses a closing link for a chain. The closing link has a narrow design and includes a pair of parallel link plates and a pair of parallel pins connected therebetween. Each plate includes an elongated hole that has a large diameter at one end to allow insertion of the pin. Each pin includes a groove near the pin head that is wider than the thickness of the link plate and the position of the groove from the end of the pin is smaller than the thickness of the link plate. The other end of the elongated hole is countersunk to such a depth that, in the installed state, the pin head latches in place and partially protrudes beyond the outer surface of the outer link plate. When connecting adjoining links of the chain, the chain pins are inserted into the inner link plates of the open chain such that the outer link plates of the closing link lie opposite each other in a mirror-inverted manner. To connect the chain, first the ends of the chain are drawn together, then the free ends of the chain pins are pushed through the larger diameter end of the elongated hole of the mating outer link plate. Upon tensioning the chain, the chain pins move along the elongated hole toward the countersink until the pin head latches into the countersink at the other end of the elongated hole. To disconnect the chain, the chain is drawn together at the closing link causing the two mating outer link plates of the closing link to slide relative to each other to dislodge the pin head out of the countersink, thereby displacing the chain pin to the larger diameter end of the elongated hole. In this position, the chain pins can be withdrawn from of the link plates thereby disconnecting the chain.
One drawback of the above closing link is that the pin head protrudes beyond the outer surface of the outer link plate which is not suitable for derailleurs with many sprockets having minimal spacing therebetween. Another drawback is that a large groove on the pin head results in undesirable lateral movement of the chain in the region of the closing link that may have an adverse effect on the shifting behavior of the chain.